alkyd synthesis & applications principles of self healing
TRANSCRIPT
Alkyd Synthesis & Applications
Topics Introduction to Alkyds & Polymers
Engineering Design ProcessFluorinated Alkyd Coatings
Encapsulation of Alkyds for CoatingsPrinciples of Self Healing Polymers
Self Healing Gelatin Laboratory
What is an Alkyd & Why Should You Care About Them? ➢
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Wait! What is a Polymer?“You act like we should know what these are.”
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So… What Gives These Polymers Their Specific Characteristics
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Ok….. So, Now I Know What A Polymer Is How Do We Make Them?
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Types of Alkyd Synthesis Used Monoglyceride Process ➢ Two Stage Process: 1) Transesterification 2) Direct Esterification➢ Temperatures between 230oC and 250oC
Fatty Acid Process ➢ One Step process that offers better control, but at a higher cost than the Monoglyceride process.➢ In this Process the esterification of both aliphatic and aromatic groups occurs at the same time.
heatCatalyst
Linseed Oil R1 -Linoleic acidR2-Oleic AcidR3- Stearic Acid
Glycerol (excess) Monoglyceride Phthalic
Anhydride Alkyd Resin
heatCatalyst
Phthalic Anhydride
Alkyd ResinGlycerol
Modifying Alkyds
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Alkyd Resin Fluorinated Polyol Fluorinated Alkyd
heat
Testing Properties
Graphite Pencil Test
Tests a coatings hardness Test the adhesion strength
Measures minimum tensile stress Tests impact resistance SEM shows stratification & where atoms are
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Scanning Electron Microscope- Capsule ➢ Alkyd was encapsulated in
silica shell.➢ Not all silica formed
capsules ➢ Each Capsule consists of
about 53%/TEOS (tetraethyl orthosilicate) and 28% Silica Shell
➢ One problem is that capsules are too large for coating applications.
➢ Currently trying to make capsules smaller.
➢ Disperse and test the capsules in a coating resin.
Self Healing Polymers! Wait did you say Self Healing? But How?
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Strategies for self Healing Materials
Self Healing Gelatin Laboratory Experience
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From Calcium lactate
Sodium alginate mixed with Juice
Spheres
Why does the Calcium displace the sodium if sodium is more reactive? Entropy Driven- Entropy is increasing as 1 calcium displaces 2 Sodium ions
Sodium Polyacrylate & Water Demo
Materials
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Demonstration of Self Healing in the Gelatin
Testing the Hardness of the Gelatin Before and After Using Bloom Test for Hardness & A Durometer
Category Bloom Number
Average Molecular Mass
Low Bloom
50-125 20,000-25,000
Medium Bloom
175-225 40,000-50,000
High Bloom
225-235 50,000-100,000
References